[AMDGPU] Add intrinsics for atomic struct buffer loads (llvm#100140)

Mark these intrinsics as atomic loads within LLVM to prevent hoisting
out of loops in cases where
the load is considered invariant.

Similar to llvm#97707, but for
struct buffer loads.

Author: OutOfCache

llvm/include/llvm/IR/IntrinsicsAMDGPU.td

@@ -1200,6 +1200,23 @@ class AMDGPUStructBufferLoad<LLVMType data_ty = llvm_any_ty> : DefaultAttrsIntri
 def int_amdgcn_struct_buffer_load_format : AMDGPUStructBufferLoad;
 def int_amdgcn_struct_buffer_load : AMDGPUStructBufferLoad;
 
+class AMDGPUStructAtomicBufferLoad<LLVMType data_ty = llvm_any_ty> : Intrinsic <
+  [data_ty],
+  [llvm_v4i32_ty,    // rsrc(SGPR)
+   llvm_i32_ty,      // vindex(VGPR)
+   llvm_i32_ty,      // offset(VGPR/imm, included in bounds checking and swizzling)
+   llvm_i32_ty,      // soffset(SGPR/imm, excluded from bounds checking and swizzling)
+   llvm_i32_ty],     // auxiliary/cachepolicy(imm):
+                     //                bit 0 = glc, bit 1 = slc, bit 2 = dlc (gfx10/gfx11),
+                     //                bit 3 = swz, bit 4 = scc (gfx90a)
+                     //        gfx940: bit 0 = sc0, bit 1 = nt, bit 3 = swz, bit 4 = sc1
+                     //        gfx12+: bits [0-2] = th, bits [3-4] = scope,
+                     //                bit 6 = swz
+                     //           all: volatile op (bit 31, stripped at lowering)
+  [ImmArg<ArgIndex<4>>, IntrWillReturn, IntrNoCallback, IntrNoFree], "", [SDNPMemOperand]>,
+  AMDGPURsrcIntrinsic<0>;
+def int_amdgcn_struct_atomic_buffer_load : AMDGPUStructAtomicBufferLoad;
+
 class AMDGPUStructPtrBufferLoad<LLVMType data_ty = llvm_any_ty> : DefaultAttrsIntrinsic <
   [data_ty],
   [AMDGPUBufferRsrcTy,    // rsrc(SGPR)
@@ -1219,6 +1236,24 @@ class AMDGPUStructPtrBufferLoad<LLVMType data_ty = llvm_any_ty> : DefaultAttrsIn
 def int_amdgcn_struct_ptr_buffer_load_format : AMDGPUStructPtrBufferLoad;
 def int_amdgcn_struct_ptr_buffer_load : AMDGPUStructPtrBufferLoad;
 
+class AMDGPUStructPtrAtomicBufferLoad<LLVMType data_ty = llvm_any_ty> : Intrinsic <
+  [data_ty],
+  [AMDGPUBufferRsrcTy,    // rsrc(SGPR)
+   llvm_i32_ty,           // vindex(VGPR)
+   llvm_i32_ty,           // offset(VGPR/imm, included in bounds checking and swizzling)
+   llvm_i32_ty,           // soffset(SGPR/imm, excluded from bounds checking and swizzling)
+   llvm_i32_ty],          // auxiliary/cachepolicy(imm):
+                          //                bit 0 = glc, bit 1 = slc, bit 2 = dlc (gfx10/gfx11),
+                          //                bit 3 = swz, bit 4 = scc (gfx90a)
+                          //        gfx940: bit 0 = sc0, bit 1 = nt, bit 3 = swz, bit 4 = sc1
+                          //        gfx12+: bits [0-2] = th, bits [3-4] = scope,
+                          //                bit 6 = swz
+                          //           all: volatile op (bit 31, stripped at lowering)
+  [IntrArgMemOnly, NoCapture<ArgIndex<0>>,
+   ImmArg<ArgIndex<4>>, IntrWillReturn, IntrNoCallback, IntrNoFree], "", [SDNPMemOperand]>,
+  AMDGPURsrcIntrinsic<0>;
+def int_amdgcn_struct_ptr_atomic_buffer_load : AMDGPUStructPtrAtomicBufferLoad;
+
 class AMDGPURawBufferStore<LLVMType data_ty = llvm_any_ty> : DefaultAttrsIntrinsic <
   [],
   [data_ty,          // vdata(VGPR)

llvm/lib/Target/AMDGPU/AMDGPULegalizerInfo.cpp

@@ -7375,6 +7375,8 @@ bool AMDGPULegalizerInfo::legalizeIntrinsic(LegalizerHelper &Helper,
   case Intrinsic::amdgcn_raw_ptr_atomic_buffer_load:
   case Intrinsic::amdgcn_struct_buffer_load:
   case Intrinsic::amdgcn_struct_ptr_buffer_load:
+  case Intrinsic::amdgcn_struct_atomic_buffer_load:
+  case Intrinsic::amdgcn_struct_ptr_atomic_buffer_load:
     return legalizeBufferLoad(MI, MRI, B, false, false);
   case Intrinsic::amdgcn_raw_buffer_load_format:
   case Intrinsic::amdgcn_raw_ptr_buffer_load_format:

llvm/lib/Target/AMDGPU/AMDGPURegisterBankInfo.cpp

@@ -5020,7 +5020,9 @@ AMDGPURegisterBankInfo::getInstrMapping(const MachineInstr &MI) const {
     case Intrinsic::amdgcn_struct_buffer_load:
     case Intrinsic::amdgcn_struct_ptr_buffer_load:
     case Intrinsic::amdgcn_struct_tbuffer_load:
-    case Intrinsic::amdgcn_struct_ptr_tbuffer_load: {
+    case Intrinsic::amdgcn_struct_ptr_tbuffer_load:
+    case Intrinsic::amdgcn_struct_atomic_buffer_load:
+    case Intrinsic::amdgcn_struct_ptr_atomic_buffer_load: {
       OpdsMapping[0] = getVGPROpMapping(MI.getOperand(0).getReg(), MRI, *TRI);
       OpdsMapping[2] = getSGPROpMapping(MI.getOperand(2).getReg(), MRI, *TRI);
       OpdsMapping[3] = getVGPROpMapping(MI.getOperand(3).getReg(), MRI, *TRI);

llvm/lib/Target/AMDGPU/SIISelLowering.cpp

@@ -1278,7 +1278,9 @@ bool SITargetLowering::getTgtMemIntrinsic(IntrinsicInfo &Info,
         return true;
       }
       case Intrinsic::amdgcn_raw_atomic_buffer_load:
-      case Intrinsic::amdgcn_raw_ptr_atomic_buffer_load: {
+      case Intrinsic::amdgcn_raw_ptr_atomic_buffer_load:
+      case Intrinsic::amdgcn_struct_atomic_buffer_load:
+      case Intrinsic::amdgcn_struct_ptr_atomic_buffer_load: {
         Info.memVT =
             memVTFromLoadIntrReturn(*this, MF.getDataLayout(), CI.getType(),
                                     std::numeric_limits<unsigned>::max());
@@ -8925,7 +8927,9 @@ SDValue SITargetLowering::LowerINTRINSIC_W_CHAIN(SDValue Op,
   case Intrinsic::amdgcn_struct_buffer_load:
   case Intrinsic::amdgcn_struct_ptr_buffer_load:
   case Intrinsic::amdgcn_struct_buffer_load_format:
-  case Intrinsic::amdgcn_struct_ptr_buffer_load_format: {
+  case Intrinsic::amdgcn_struct_ptr_buffer_load_format:
+  case Intrinsic::amdgcn_struct_atomic_buffer_load:
+  case Intrinsic::amdgcn_struct_ptr_atomic_buffer_load: {
     const bool IsFormat =
         IntrID == Intrinsic::amdgcn_struct_buffer_load_format ||
         IntrID == Intrinsic::amdgcn_struct_ptr_buffer_load_format;